Brushes for cleaning the inner surfaces of vessels are well known in the art. One type of such brush is the twisted in wire brush, which is commonly used in a variety of applications including, but not limited to, hole cleaning, sanding, deburring or lubricating, tube or vessel cleaning, beaker cleaning, pistol, rifle and shotgun cleaning, medical equipment cleaning, medical and dental procedures, medical applications and the application of personal care products including mascara and the like. Twisted in wire brushes are also known as spiral, tube flue, bottle, pipe, boiler or power brushes, and are generally comprised of a plurality of bristles held and secured by a pair of twisted metal wires which form the core of the brush. The bristles are often formed from some type of acrylic fiber and extend radially from the core or longitudinal axis of the brush, generally resulting in a roughly cylindrical appearance. It will be readily appreciated, however, that the bristles may be formed from any suitable material including metal, such as stainless steel, brass or bronze, nylon, Teflon, polypropylene, horse or hog hair, depending on the specific use. Moreover, depending on the specification application, the ends of the brush can also vary. For example, a brush may have a rough-cut tip, a rounded tip or a bristled or fan tip, and can have a long end or handle, a short end, or a finished end having various configurations such as a ring or loop.
During the manufacturing of known brushes, the core of the brush, i.e., the twisted wire, is often cut at a distal or bristle end thereof, opposite the handle end. This cutting may leave a sharp, uneven and unfinished end. Known twisted in wire brushes may also employ a continuous end where the wire is doubled back on itself prior to twisting, as shown in prior art FIGS. 1A and 1B. The subsequent twisting to secure the bristles often leaves this continuous end (opposite the unfinished end) with rough, sharp and uneven surfaces and edges as well. This is highly undesirable in applications as discussed in detail below, where a smooth and frictionless surface is needed at the end of the brush so as to be less prone to scratch, scar or damage sensitive cleaning surfaces.
As alluded to above, twisted in wire brushes are used in many applications where an unfinished or uneven end of a brush would cause scratching or other damage. For example, such twisted wire brushes have particular application in the medical field where they are used for, among other things, cleaning the inner surfaces of catheters, arthroscopic devices, cameras, etc. Moreover, specialized brushes have been known to be used directly on or in soft and delicate tissues or cavities such as blood vessels. Accordingly, there is a need to have a finished tip on twisted in wire brushed so that a smooth and frictionless surface is presented to the interior of the vessel or cavity to be cleaned.
In view of this need, there exist several different known technologies and methods which are used to form rounded or smooth ends on twisted wire brushes in an attempt to prevent the ends of the wire core from scratching or otherwise damaging the inner walls of a vessel. One such method involves press-fitting or hand-crimping a small metal cap on the end of the brush to form a smooth and rounded tip. This process, however, is quite labor-intensive and time consuming, resulting in high labor and production costs. In addition, this method often results in inconsistent tip orientation, i.e., the metal caps are often improperly seated on the end of the brush. This increases the chance that the caps will be dislodged or displaced, which can itself create an uneven surface or expose the unfinished end of the brush, thereby resulting in scratching or damage to the interior surface of the cavity being cleaned. Moreover, this method of forming a smooth tip may result in inconsistent core wire adhesion and only allows for limited dimensional options.
Another known method of providing a smooth end on a twisted wire brush involves dipping the end of the brush into a vat of plastic or acrylic and then exposing the tip to visible or ultraviolet light to cure the plastic or acrylic. Such process results in the formation of a protective plastic or acrylic tip on the end of the brush. This method, however, often results in a rough surface texture and inconsistent tip dimensions due to both the viscosity of the plastic or acrylic used, and the time it takes for such plastic or acrylic to cure. Such rough tips are highly undesirable for use in applications where a smooth surface is needed to prevent damage to soft and sensitive vessel walls that may be prone to scratching or other damage. Moreover, even when employing this method, it is possible that the wire core section may protrude through the plastic tip during use, thereby exposing a sharp and unfinished end of the core wire section to such sensitive surfaces. These plastic or acrylic tips are also prone to dislodgment, which can result in exposure of the unfinished core wire section. Additionally, manufacturing time may be greatly increased due to extended curing times, and hazardous fumes may result from the dipping and curing process. Light curing the tips also involves semi-automatic or manual processes that may be time consuming and may result in increased labor and production costs. Moreover, as will be readily appreciated, in many applications, it is desirable to color code the tips of the brushes so as to identify the brush by type, size or use. The acrylic/plastic tip method, however, only allows for limited/inconsistent tip color options.
Insert molding is yet another known method for forming a rounded tip on the end of a brush, and involves placing the end of the brush into a mold and then injecting plastic into the mold. When the plastic hardens, the brush end is removed from the mold, producing a hardened, rounded plastic cap on the end of the brush. This method, likewise, is not without its drawbacks. Due to the high cost of mold making, it is impractical for small production runs. In addition, this process may result in core wire protrusion through the plastic tip, either from the molding process or through forces associated with cleaning. In addition, the protective tip may be inadvertently dislodged from the wire core during use, resulting in exposure of the sharp end of the core wire and potential damage to interior vessel walls. This method also does not allow for many variations in tip sizes and may result in inconsistent tip orientation. Such an inconsistent or angled tip orientation may itself cause damage to the surface to be cleaned or may cause the tip to be jarred loose during cleaning, resulting in exposure of the core wire.
Fan-tip twisted in wire brushes are another attempt to provide a protective surface on the brush end. This type of brush features “fanned” bristles on the brush end in attempt to shield the surface to be cleaned from the end of the brush. Fan-tip twisted in wire brushes, however, are less commercially attractive, have limited fan tip dimensions, and have increased production costs. In addition, during use, depending on the interaction between the bristles and the surface being cleaned, the core wire may still be exposed through the fan tip, thereby potentially causing damage to any sensitive surface.
Another inherent problem with twisted in wire brushes in general is their tendency to unravel when used in applications such as medical applications and gun cleaning where a reasonable force is necessary to effectuate cleaning, deburring, etc. In such applications, the forces generated by the cleaning motion will sometimes cause the twisted wire core to come unraveled and the bristles to become dislodged. This may cause exposure of the core wires, making the vessel more prone to scratching and other damage, and also may result in the leaving of undesirable debris, e.g., bristles or caps, within the vessel. There is therefore a need to increase the structural strength of such brushes so as to prevent unraveling in applications where a reasonable force is needed to effectuate cleaning, deburring, lubricating, etc.
In view of the problems associated with known techniques and methods for forming a rounded or smooth tip on the ends of twisted wire brushes, there is a need for an improved brush and method for forming a smooth and rounded tip on the end thereof so as to prevent unintended scarring, scratching or damage to sensitive surfaces.